AMD Ryzen 9 3900X vs AMD Ryzen 9 PRO 5945 Comparison

Where Each One Wins

The AMD Ryzen 9 PRO 5945 and AMD Ryzen 9 3900X split their 15 recorded head-to-head benchmarks, with the PRO 5945 taking 9 wins and the 3900X taking 6. That split is not evenly distributed by workload type, and the margin patterns tell a clear story.

The PRO 5945 dominates in single-threaded and lightly threaded workloads. In Cinebench R15 single-core it scores 417 against 207 for the 3900X, a 101.4% advantage. In Cinebench R23 single-core the gap widens further: 4145 versus 1370, a 202.6% lead. PassMark single-thread results show the same trend, with the PRO 5945 at 3499 versus 2703, a 29.4% edge. This is the processor for applications that reward high per-core performance: scripting, web rendering, legacy code paths, and any task that cannot spread across many threads.

The PRO 5945 also takes the multi-threaded crown in the modern Cinebench R23 test, scoring 29366 against 19000 for the 3900X, a 54.6% lead. It wins PassMark multithread as well, 34549 versus 32544, a 6.2% margin. The PRO 5945 further shows strength in math-heavy synthetic workloads: PassMark integer math goes to the PRO 5945 at 129768 versus 99628 (30.3% ahead), floating point math goes its way at 70291 versus 58434 (20.3% ahead), and it wins find prime numbers at 228 versus 214 (6.5% ahead).

The 3900X, by contrast, holds its ground in a set of specific PassMark subtests. It wins data compression 448906 versus 416599, a 7.2% edge. It wins data encryption 28586 versus 26313, an 8% margin. It wins extended instructions 29221 versus 27031, a 7.5% lead. It wins random string sorting 48300 versus 43447, a 10% margin. And it takes Cinebench R15 multi-core 3049 versus 2959, a 3% lead. The physics subtest is nearly a tie, with the 3900X ahead by 1.2% (1794 versus 1772).

The practical split: the PRO 5945 is the better all-rounder for modern software that uses current instruction sets and scales well across cores. The 3900X retains an edge in specific compression, encryption, and string-manipulation routines that apparently favor its older design in these recorded measurements.

Architecture Differences

Both processors are 12-core, 24-thread desktop parts on AMD Socket AM4, built by TSMC on a 7 nm node, with identical cache geometry: 64 KB L1 per core, 512 KB L2 per core, and 64 MB L3. Both are dual-channel DDR4 parts with a memory bandwidth of 51.2 GB/s. Both have no integrated graphics.

The architectural divide comes down to generation. The PRO 5945 is a 5000 series part using the Zen 3 architecture, codename Vermeer. The 3900X is a 3000 series part using the Zen 2 architecture, codename Matisse. Both use two chiplets with a combined die size of 2x 74 mm², but the transistor counts differ: the PRO 5945 integrates 8,300 million transistors versus 7,600 million for the 3900X. That transistor budget, combined with the newer Zen 3 core design, explains much of the performance gap.

Clock behavior also differs. The PRO 5945 has a base clock of 3.00 GHz and a boost clock of 4.70 GHz, while the 3900X runs a higher base of 3.80 GHz but a lower boost of 4.60 GHz. The 3900X's higher base clock helps it in the older Cinebench R15 multi-core test and some PassMark subtests, while the PRO 5945's higher boost and better IPC carry it in single-thread and modern multi-thread workloads.

Power is a major differentiator. The PRO 5945 carries a 65 W TDP, the 3900X a 105 W TDP. The PRO 5945 delivers more performance in most modern benchmarks while drawing a lower rated power envelope, which points to the efficiency gains of the newer architecture.

PCIe lane counts differ. The PRO 5945 provides Gen 4 with 20 lanes (CPU only), while the 3900X provides Gen 4 with 24 lanes (CPU only). Both support DDR4 memory, but the PRO 5945 supports ECC memory while the 3900X does not.

Other differences: the PRO 5945 has a locked multiplier, while the 3900X has an unlocked multiplier. The 3900X launched with an MSRP of $499; the PRO 5945 has no recorded launch MSRP. The PRO 5945 released in April 2022, the 3900X in July 2019.

Head-to-Head Benchmarks

The single-core results are the most striking. In Cinebench R15 single-core, the PRO 5945 scores 417 versus 207, a 101.4% advantage: it more than doubles the 3900X's score. In Cinebench R23 single-core, the PRO 5945 scores 4145 versus 1370, a 202.6% advantage, meaning the 3900X manages only about a third of the newer chip's score. PassMark single-thread shows a more moderate but still decisive 29.4% gap, 3499 versus 2703.

Multi-core results are more nuanced. The 3900X wins Cinebench R15 multi-core 3049 versus 2959, a 3% margin. But in Cinebench R23 multi-core, the PRO 5945 wins decisively: 29366 versus 19000, a 54.6% lead. The R15 test is older and less demanding on memory and instruction throughput, which appears to favor the 3900X's higher base clock. The R23 test is more representative of modern heavily threaded workloads, and there the Zen 3 design pulls far ahead.

In PassMark subtests, the 3900X wins four of them by single-digit to low-double-digit margins: data compression by 7.2% (448906 versus 416599), data encryption by 8% (28586 versus 26313), extended instructions by 7.5% (29221 versus 27031), and random string sorting by 10% (48300 versus 43447). The physics subtest goes to the 3900X by just 1.2% (1794 versus 1772), effectively a tie.

The PRO 5945 wins the remaining PassMark subtests, often by larger margins. Integer math is its biggest win: 129768 versus 99628, a 30.3% gap. Floating point math follows at 20.3% (70291 versus 58434). Find prime numbers goes to the PRO 5945 by 6.5% (228 versus 214), and PassMark multithread goes to it by 6.2% (34549 versus 32544).

Overall database averages put the PRO 5945 at 47527 average benchmark score with a 90th percentile versus all CPUs, while the 3900X sits at 46487 with an 89th percentile. The PRO 5945's nearest rivals are the Intel Core Ultra X9 378H (0.1% ahead), Intel Core Ultra 7 265T (0.4% behind), Intel Core i7-13700KF (0.4% behind), and Intel Core i9-12900F (0.7% behind). The 3900X's nearest rivals are the Intel Xeon w3-2535 (0.4% behind), AMD Ryzen 9 7845HX (0.4% behind), AMD Ryzen AI 5 440G (0.6% ahead), and Intel Core i9-13900HX (0.8% ahead).

The Verdict

The data supports a clear recommendation for most builders: the AMD Ryzen 9 PRO 5945 is the stronger processor in the majority of recorded benchmarks, and its wins come in the workload categories that matter most for modern desktop use. It is 202.6% ahead in Cinebench R23 single-core, 54.6% ahead in Cinebench R23 multi-core, 30.3% ahead in integer math, and 20.3% ahead in floating point math. It also does all of this within a 65 W TDP, versus 105 W for the 3900X.

The 3900X is not obsolete across the board. Its wins in data compression, data encryption, extended instructions, random string sorting, and Cinebench R15 multi-core mean that users whose workloads are dominated by those specific routines may see no benefit from switching. The margins there are modest, 3% to 10%, not the kind of generational leap the PRO 5945 shows in other tests. But those wins are narrow, and they come in a minority of the recorded tests.

The PRO 5945 is the pick for anyone running current software, especially anything that benefits from high single-thread performance or well-threaded modern workloads. Its 29.4% lead in PassMark single-thread and its 54.6% lead in Cinebench R23 multi-core are the kind of margins that translate into visibly faster daily use, faster compilation, faster rendering, and faster response in latency-sensitive tasks.

The 3900X makes sense only for a narrow use case: workloads that are specifically heavy in the PassMark subtests it wins, or users who need the unlocked multiplier for overclocking, which the PRO 5945 does not offer. For everything else, the PRO 5945 is the better choice, and it does so at a lower rated power draw.

FAQ

Q: Which processor is faster in single-core performance?

A: The AMD Ryzen 9 PRO 5945 wins every recorded single-thread test. It leads by 101.4% in Cinebench R15 single-core, 202.6% in Cinebench R23 single-core, and 29.4% in PassMark single-thread.

Q: Does the older Ryzen 9 3900X win any benchmarks?

A: Yes, it wins 6 of 15 head-to-head tests: Cinebench R15 multi-core, PassMark data compression, data encryption, extended instructions, random string sorting, and physics.

Q: How do the two compare in multi-threaded workloads?

A: It depends on the test. The 3900X wins Cinebench R15 multi-core by 3%, but the PRO 5945 wins Cinebench R23 multi-core by 54.6% and PassMark multithread by 6.2%.

Q: Do both processors have the same core and thread counts?

A: Yes, both have 12 cores and 24 threads, and both have 64 MB of L3 cache. The PRO 5945 uses the Zen 3 architecture, while the 3900X uses Zen 2.

Q: Is there a difference in power consumption?

A: Yes. The PRO 5945 has a 65 W TDP, while the 3900X has a 105 W TDP.

Q: Do both processors support ECC memory?

A: No. The PRO 5945 supports ECC memory, while the 3900X does not.

Specification Differences

| Specification | AMD Ryzen 9 PRO 5945 | AMD Ryzen 9 3900X |

|---|---|---|

| Series | 5000 series | 3000 series |

| Architecture | Zen 3 | Zen 2 |

| Codename | Vermeer | Matisse |

| Process node | 7 nm | 7 nm |

| Foundry | TSMC | TSMC |

| Transistors | 8,300 million | 7,600 million |

| Base clock | 3.00 GHz | 3.80 GHz |

| Boost clock | 4.70 GHz | 4.60 GHz |

| TDP | 65 W | 105 W |

| ECC memory | Yes | No |

| PCIe | Gen 4, 20 lanes (CPU only) | Gen 4, 24 lanes (CPU only) |

| Multiplier unlocked | No | Yes |

| Release date | April 2022 | July 2019 |

| Launch MSRP | None recorded | $499 |